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Hernandez AR, Barrett ME, Lubke KN, Maurer AP, Burke SN. A long-term ketogenic diet in young and aged rats has dissociable effects on prelimbic cortex and CA3 ensemble activity. Front Aging Neurosci 2023; 15:1274624. [PMID: 38155737 PMCID: PMC10753023 DOI: 10.3389/fnagi.2023.1274624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 11/20/2023] [Indexed: 12/30/2023] Open
Abstract
Introduction Age-related cognitive decline has been linked to distinct patterns of cellular dysfunction in the prelimbic cortex (PL) and the CA3 subregion of the hippocampus. Because higher cognitive functions require both structures, selectively targeting a neurobiological change in one region, at the expense of the other, is not likely to restore normal behavior in older animals. One change with age that both the PL and CA3 share, however, is a reduced ability to utilize glucose, which can produce aberrant neural activity patterns. Methods The current study used a ketogenic diet (KD) intervention, which reduces the brain's reliance on glucose, and has been shown to improve cognition, as a metabolic treatment for restoring neural ensemble dynamics in aged rats. Expression of the immediate-early genes Arc and Homer1a were used to quantify the neural ensembles that were active in the home cage prior to behavior, during a working memory/biconditional association task, and a continuous spatial alternation task. Results Aged rats on the control diet had increased activity in CA3 and less ensemble overlap in PL between different task conditions than did the young animals. In the PL, the KD was associated with increased activation of neurons in the superficial cortical layers, establishing a clear link between dietary macronutrient content and frontal cortical activity. The KD did not lead to any significant changes in CA3 activity. Discussion These observations suggest that the availability of ketone bodies may permit the engagement of compensatory mechanisms in the frontal cortices that produce better cognitive outcomes.
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Affiliation(s)
- Abbi R. Hernandez
- Division of Gerontology, Geriatrics, and Palliative Care, Department of Medicine, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Maya E. Barrett
- Department of Psychology, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Katelyn N. Lubke
- Department of Neuroscience, McKnight Brain Institute, and Center for Cognitive Aging and Memory, University of Florida, Gainesville, FL, United States
| | - Andrew P. Maurer
- Department of Neuroscience, McKnight Brain Institute, and Center for Cognitive Aging and Memory, University of Florida, Gainesville, FL, United States
| | - Sara N. Burke
- Department of Neuroscience, McKnight Brain Institute, and Center for Cognitive Aging and Memory, University of Florida, Gainesville, FL, United States
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Hernandez AR, Barrett ME, Lubke KN, Maurer AP, Burke SN. A long-term ketogenic diet in young and aged rats has dissociable effects on prelimbic cortex and CA3 ensemble activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.18.529095. [PMID: 36824737 PMCID: PMC9949134 DOI: 10.1101/2023.02.18.529095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Age-related cognitive decline has been linked to distinct patterns of cellular dysfunction in the prelimbic cortex (PL) and the CA3 subregion of the hippocampus. Because higher cognitive functions require both structures, selectively targeting a neurobiological change in one region, at the expense of the other, is not likely to restore normal behavior in older animals. One change with age that both the PL and CA3 share, however, is a reduced ability to utilize glucose, which can produce aberrant neural activity patterns. The current study used a ketogenic diet (KD) intervention, which reduces the brain’s reliance on glucose, and has been shown to improve cognition, as a metabolic treatment for restoring neural ensemble dynamics in aged rats. Expression of the immediate-early genes Arc and Homer 1a were used to quantify the neural ensembles that were active in the home cage prior to behavior, during a working memory/biconditional association task, and a continuous spatial alternation task. Aged rats on the control diet had increased activity in CA3 and less ensemble overlap in PL between different task conditions than did the young animals. In the PL, the KD was associated with increased activation of neurons in the superficial cortical layers. The KD did not lead to any significant changes in CA3 activity. These observations suggest that the KD does not restore neuron activation patterns in aged animals, but rather the availability of ketone bodies in the frontal cortices may permit the engagement of compensatory mechanisms that produce better cognitive outcomes. Significance Statement This study extends understanding of how a ketogenic diet (KD) intervention may improve cognitive function in older adults. Young and aged rats were given 3 months of a KD or a calorie-match control diet and then expression of the immediate-early genes Arc and Homer 1a were measured to examine neural ensemble dynamics during cognitive testing. The KD diet was associated with increased activation of neurons in the superficial layers of the PL, but there were no changes in CA3. These observations are significant because they suggest that compensatory mechanisms for improving cognition are engaged in the presence of elevated ketone bodies. This metabolic shift away from glycolysis can meet the energetic needs of the frontal cortices when glucose utilization is compromised.
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Yu J, He Y, Yu X, Gu L, Wang Q, Wang S, Tao F, Sheng J. Associations Between Mild Cognitive Impairment and Whole Blood Zinc and Selenium in the Elderly Cohort. Biol Trace Elem Res 2023; 201:51-64. [PMID: 35113349 DOI: 10.1007/s12011-022-03136-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/24/2022] [Indexed: 01/11/2023]
Abstract
Some studies have shown that an imbalance in trace element homeostasis can lead to cognitive dysfunction, but data are lacking. The purpose of this study was to investigate the association between whole blood zinc (Zn), selenium (Se), copper-zinc ratio (Cu/Zn), copper-selenium ratio (Cu/Se), and zinc-selenium ratio (Zn/Se) and mild cognitive impairment (MCI) in elderly Chinese individuals. The study was based on the Elderly Health and Controlled Environmental Factors Cohort in Lu'an, Anhui Province, China, from June to September 2016. The cognitive function of the elderly was determined by the Mini-Mental State Examination (MMSE) and activities of daily living (ADL) scales. The concentrations of Zn, Cu, and Se in the whole blood were measured by inductively coupled plasma-mass spectrometry (ICP-MS). Binary logistic regression was used to analyze the associations between trace elements and MCI. A total of 1006 participants with an average age of 71.70 years old were included in this study. Compared with healthy people, MCI patients had higher whole blood Zn levels and lower Se levels, and Cu/Zn, Cu/Se, and Zn/Se were also significantly different. Binary logistic regression analysis showed that Zn, Cu/Se, and Zn/Se exposure in the third tertile was associated with an increased risk of MCI, while Se exposure in the third tertile was associated with a reduced risk of MCI. After adjustment for sex, age, marital status, BMI, and living status, whole blood Zn, Se, Cu/Zn, Cu/Se, and Zn/Se were significantly associated with MCI risk, especially in elderly women.
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Affiliation(s)
- Jinhui Yu
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, 230032, Anhui, China
| | - Yu He
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, 230032, Anhui, China
| | - Xuemin Yu
- School of Public Health, Anhui Medical University, Hefei, 230032, Anhui, China
| | - Ling Gu
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, 230032, Anhui, China
- Changzhou Center for Disease Control and Prevention, Changzhou, 213000, Jiangsu, China
| | - Qunan Wang
- School of Public Health, Anhui Medical University, Hefei, 230032, Anhui, China
| | - Sufang Wang
- School of Public Health, Anhui Medical University, Hefei, 230032, Anhui, China
| | - Fangbiao Tao
- School of Public Health, Anhui Medical University, Hefei, 230032, Anhui, China
- MOE Key Laboratory of Population Health Across Life Cycle/Anhui Provincial Key Laboratory of Population Health and Aristogenics, Hefei, 230032, Anhui, China
| | - Jie Sheng
- School of Public Health, Anhui Medical University, Hefei, 230032, Anhui, China.
- MOE Key Laboratory of Population Health Across Life Cycle/Anhui Provincial Key Laboratory of Population Health and Aristogenics, Hefei, 230032, Anhui, China.
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4
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Engel MG, Smith J, Mao K, Quipildor GF, Cui MH, Gulinello M, Branch CA, Gandy SE, Huffman DM. Evidence for preserved insulin responsiveness in the aging rat brain. GeroScience 2022; 44:2491-2508. [PMID: 35798912 PMCID: PMC9768080 DOI: 10.1007/s11357-022-00618-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 06/27/2022] [Indexed: 01/06/2023] Open
Abstract
Insulin appears to exert salutary effects in the central nervous system (CNS). Thus, brain insulin resistance has been proposed to play a role in brain aging and dementia but is conceptually complex and unlikely to fit classic definitions established in peripheral tissues. Thus, we sought to characterize brain insulin responsiveness in young (4-5 months) and old (24 months) FBN male rats using a diverse set of assays to determine the extent to which insulin effects in the CNS are impaired with age. When performing hyperinsulinemic-euglycemic clamps in rats, intracerebroventricular (ICV) infusion of insulin in old animals improved peripheral insulin sensitivity by nearly two-fold over old controls and comparable to young rats, suggesting preservation of this insulin-triggered response in aging per se (p < 0.05). We next used an imaging-based approach by comparing ICV vehicle versus insulin and performed resting state functional magnetic resonance imaging (rs-fMRI) to evaluate age- and insulin-related changes in network connectivity within the default mode network. In aging, lower connectivity between the mesial temporal (MT) region and other areas, as well as reduced MT signal complexity, was observed in old rats, which correlated with greater cognitive deficits in old. Despite these stark differences, ICV insulin failed to elicit any significant alteration to the BOLD signal in young rats, while a significant deviation of the BOLD signal was observed in older animals, characterized by augmentation in regions of the septal nucleus and hypothalamus, and reduction in thalamus and nucleus accumbens. In contrast, ex vivo stimulation of hippocampus with 10 nM insulin revealed increased Akt activation in young (p < 0.05), but not old rats. Despite similar circulating levels of insulin and IGF-1, cerebrospinal fluid concentrations of these ligands were reduced with age. Thus, these data highlight the complexity of capturing brain insulin action and demonstrate preserved or heightened brain responses to insulin with age, despite dampened canonical signaling, thereby suggesting impaired CNS input of these ligands may be a feature of reduced brain insulin action, providing further rationale for CNS replacement strategies.
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Affiliation(s)
- Matthew G Engel
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, 1300 Morris Park Ave, Golding Building Room 201, BronxBronx, NY, 10461, USA
| | - Jeremy Smith
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA
| | - Kai Mao
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, 1300 Morris Park Ave, Golding Building Room 201, BronxBronx, NY, 10461, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Gabriela Farias Quipildor
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Institute for Aging Research, Albert Einstein College of Medicine, 1300 Morris Park Ave, Golding Building Room 201, BronxBronx, NY, 10461, USA
| | - Min-Hui Cui
- Department of Radiology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Maria Gulinello
- Dominick S. Purpura Department of Neuroscience, Behavioral Core Facility, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Craig A Branch
- Department of Radiology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Samuel E Gandy
- Department of Neurology and the Mount Sinai Center for Cognitive Health, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry and the Mount Sinai Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Derek M Huffman
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
- Institute for Aging Research, Albert Einstein College of Medicine, 1300 Morris Park Ave, Golding Building Room 201, BronxBronx, NY, 10461, USA.
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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Baltaci SB, Unal O, Gulbahce-Mutlu E, Gumus H, Pehlivanoglu S, Yardimci A, Mogulkoc R, Baltaci AK. The Role of Zinc Status on Spatial Memory, Hippocampal Synaptic Plasticity, and Insulin Signaling in icv-STZ-Induced Sporadic Alzheimer's-Like Disease in Rats. Biol Trace Elem Res 2022; 200:4068-4078. [PMID: 34727320 DOI: 10.1007/s12011-021-02999-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 10/26/2021] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD), especially its sporadic form (sAD), is of multifactorial nature. Brain insulin resistance and disrupted zinc homeostasis are two key aspects of AD that remain to be elucidated. Here, we investigated the effects of dietary zinc deficiency and supplementation on memory, hippocampal synaptic plasticity, and insulin signaling in intracerebroventricular streptozotocin (icv-STZ)-induced sAD in rats. The memory performance was evaluated by Morris water maze. The expression of hippocampal protein and mRNA levels of targets related to synaptic plasticity and insulin pathway was assessed by Western blot and real-time quantitative PCR. We found memory deficits in icv-STZ rats, which were fully recovered by zinc supplementation. Western blot analysis revealed that icv-STZ treatment significantly reduced hippocampal PSD95 and p-GSK3β, and zinc supplementation restored the normal protein levels. mRNA levels of BDNF, PSD95, SIRT1, GLUT4, insulin receptor, and ZnT3 were found to be reduced by icv-STZ and reestablished by zinc supplementation. Our data suggest that zinc supplementation improves cognitive deficits and rescues the decline in key molecular targets of synaptic plasticity and insulin signaling in hippocampus caused by icv-STZ induced sAD in rats.
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Affiliation(s)
- Saltuk Bugra Baltaci
- Department of Physiology, Medical Faculty, Selçuk University, Konya, 42031, Turkey
| | - Omer Unal
- Department of Physiology, Medical Faculty, Selçuk University, Konya, 42031, Turkey
| | - Elif Gulbahce-Mutlu
- Department of Medical Biology, Medical Faculty, KTO Karatay University, Konya, Turkey
| | - Haluk Gumus
- Department of Neurology, Medical Faculty, Selçuk University, Konya, Turkey
| | - Suray Pehlivanoglu
- Department of Molecular Biology, Science Faculty, Necmettin Erbakan University, Konya, Turkey
| | - Ahmet Yardimci
- Department of Physiology, Medical Faculty, Firat University, Elazig, Turkey
| | - Rasim Mogulkoc
- Department of Physiology, Medical Faculty, Selçuk University, Konya, 42031, Turkey
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Falling Short: The Contribution of Central Insulin Receptors to Gait Dysregulation in Brain Aging. Biomedicines 2022; 10:biomedicines10081923. [PMID: 36009470 PMCID: PMC9405648 DOI: 10.3390/biomedicines10081923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/27/2022] [Accepted: 07/29/2022] [Indexed: 11/23/2022] Open
Abstract
Insulin resistance, which manifests as a reduction of insulin receptor signaling, is known to correlate with pathological changes in peripheral tissues as well as in the brain. Central insulin resistance has been associated with impaired cognitive performance, decreased neuronal health, and reduced brain metabolism; however, the mechanisms underlying central insulin resistance and its impact on brain regions outside of those associated with cognition remain unclear. Falls are a leading cause of both fatal and non-fatal injuries in the older population. Despite this, there is a paucity of work focused on age-dependent alterations in brain regions associated with ambulatory control or potential therapeutic approaches to target these processes. Here, we discuss age-dependent alterations in central modalities that may contribute to gait dysregulation, summarize current data supporting the role of insulin signaling in the brain, and highlight key findings that suggest insulin receptor sensitivity may be preserved in the aged brain. Finally, we present novel results showing that administration of insulin to the somatosensory cortex of aged animals can alter neuronal communication, cerebral blood flow, and the motivation to ambulate, emphasizing the need for further investigations of intranasal insulin as a clinical management strategy in the older population.
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Lin RL, Frazier HN, Anderson KL, Case SL, Ghoweri AO, Thibault O. Sensitivity of the S1 neuronal calcium network to insulin and Bay-K 8644 in vivo: Relationship to gait, motivation, and aging processes. Aging Cell 2022; 21:e13661. [PMID: 35717599 PMCID: PMC9282843 DOI: 10.1111/acel.13661] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 05/10/2022] [Accepted: 06/05/2022] [Indexed: 01/25/2023] Open
Abstract
Neuronal hippocampal Ca2+ dysregulation is a critical component of cognitive decline in brain aging and Alzheimer's disease and is suggested to impact communication and excitability through the activation of a larger after hyperpolarization. However, few studies have tested for the presence of Ca2+ dysregulation in vivo, how it manifests, and whether it impacts network function across hundreds of neurons. Here, we tested for neuronal Ca2+ network dysregulation in vivo in the primary somatosensory cortex (S1) of anesthetized young and aged male Fisher 344 rats using single‐cell resolution techniques. Because S1 is involved in sensory discrimination and proprioception, we tested for alterations in ambulatory performance in the aged animal and investigated two potential pathways underlying these central aging‐ and Ca2+‐dependent changes. Compared to young, aged animals displayed increased overall activity and connectivity of the network as well as decreased ambulatory speed. In aged animals, intranasal insulin (INI) increased network synchronicity and ambulatory speed. Importantly, in young animals, delivery of the L‐type voltage‐gated Ca2+ channel modifier Bay‐K 8644 altered network properties, replicating some of the changes seen in the older animal. These results suggest that hippocampal Ca2+ dysregulation may be generalizable to other areas, such as S1, and might engage modalities that are associated with locomotor stability and motivation to ambulate. Further, given the safety profile of INI in the clinic and the evidence presented here showing that this central dysregulation is sensitive to insulin, we suggest that these processes can be targeted to potentially increase motivation and coordination while also reducing fall frequency with age.
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Affiliation(s)
- Ruei-Lung Lin
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Hilaree N Frazier
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Katie L Anderson
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Sami L Case
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Adam O Ghoweri
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Olivier Thibault
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, Kentucky, USA
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Erichsen JM, Calva CB, Reagan LP, Fadel JR. Intranasal insulin and orexins to treat age-related cognitive decline. Physiol Behav 2021; 234:113370. [PMID: 33621561 PMCID: PMC8053680 DOI: 10.1016/j.physbeh.2021.113370] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 02/19/2021] [Indexed: 02/06/2023]
Abstract
The intranasal (IN) administration of neuropeptides, such as insulin and orexins, has been suggested as a treatment strategy for age-related cognitive decline (ARCD). Because dysfunctional neuropeptide signaling is an observed characteristic of ARCD, it has been suggested that IN delivery of insulin and/or orexins may restore endogenous peptide signaling and thereby preserve cognition. IN administration is particularly alluring as it is a relatively non-invasive method that directly targets peptides to the brain. Several laboratories have examined the behavioral effects of IN insulin in young, aged, and cognitively impaired rodents and humans. These studies demonstrated improved performance on various cognitive tasks following IN insulin administration. Fewer laboratories have assessed the effects of IN orexins; however, this peptide also holds promise as an effective treatment for ARCD through the activation of the cholinergic system and/or the reduction of neuroinflammation. Here, we provide a brief overview of the advantages of IN administration and the delivery pathway, then summarize the current literature on IN insulin and orexins. Additional preclinical studies will be useful to ultimately uncover the mechanisms underlying the pro-cognitive effects of IN insulin and orexins, whereas future clinical studies will aid in the determination of the most efficacious dose and dosing paradigm. Eventually, IN insulin and/or orexin administration may be a widely used treatment strategy in the clinic for ARCD.
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Affiliation(s)
- Jennifer M Erichsen
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States.
| | - Coleman B Calva
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States
| | - Lawrence P Reagan
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States; Columbia VA Health Care System, Columbia, SC, 29208, United States
| | - Jim R Fadel
- University of South Carolina School of Medicine, Department of Pharmacology, Physiology, and Neuroscience, Columbia, SC 29208, United States
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9
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Targeting impaired nutrient sensing with repurposed therapeutics to prevent or treat age-related cognitive decline and dementia: A systematic review. Ageing Res Rev 2021; 67:101302. [PMID: 33609776 DOI: 10.1016/j.arr.2021.101302] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Dementia is a debilitating syndrome that significantly impacts individuals over the age of 65 years. There are currently no disease-modifying treatments for dementia. Impairment of nutrient sensing pathways has been implicated in the pathogenesis of dementia, and may offer a novel treatment approach for dementia. AIMS This systematic review collates all available evidence for Food and Drug Administration (FDA)-approved therapeutics that modify nutrient sensing in the context of preventing cognitive decline or improving cognition in ageing, mild cognitive impairment (MCI), and dementia populations. METHODS PubMed, Embase and Web of Science databases were searched using key search terms focusing on available therapeutics such as 'metformin', 'GLP1', 'insulin' and the dementias including 'Alzheimer's disease' and 'Parkinson's disease'. Articles were screened using Covidence systematic review software (Veritas Health Innovation, Melbourne, Australia). The risk of bias was assessed using the Cochrane Risk of Bias tool v 2.0 for human studies and SYRCLE's risk of bias tool for animal studies. RESULTS Out of 2619 articles, 114 were included describing 31 different 'modulation of nutrient sensing pathway' therapeutics, 13 of which specifically were utilized in human interventional trials for normal ageing or dementia. Growth hormone secretagogues improved cognitive outcomes in human mild cognitive impairment, and potentially normal ageing populations. In animals, all investigated therapeutic classes exhibited some cognitive benefits in dementia models. While the risk of bias was relatively low in human studies, this risk in animal studies was largely unclear. CONCLUSIONS Modulation of nutrient sensing pathway therapeutics, particularly growth hormone secretagogues, have the potential to improve cognitive outcomes. Overall, there is a clear lack of translation from animal models to human populations.
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Frazier HN, Ghoweri AO, Sudkamp E, Johnson ES, Anderson KL, Fox G, Vatthanaphone K, Xia M, Lin RL, Hargis-Staggs KE, Porter NM, Pauly JR, Blalock EM, Thibault O. Long-Term Intranasal Insulin Aspart: A Profile of Gene Expression, Memory, and Insulin Receptors in Aged F344 Rats. J Gerontol A Biol Sci Med Sci 2021; 75:1021-1030. [PMID: 31180116 DOI: 10.1093/gerona/glz105] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Indexed: 02/06/2023] Open
Abstract
Intranasal insulin is a safe and effective method for ameliorating memory deficits associated with pathological brain aging. However, the impact of different formulations and the duration of treatment on insulin's efficacy and the cellular processes targeted by the treatment remain unclear. Here, we tested whether intranasal insulin aspart, a short-acting insulin formulation, could alleviate memory decline associated with aging and whether long-term treatment affected regulation of insulin receptors and other potential targets. Outcome variables included measures of spatial learning and memory, autoradiography and immunohistochemistry of the insulin receptor, and hippocampal microarray analyses. Aged Fischer 344 rats receiving long-term (3 months) intranasal insulin did not show significant memory enhancement on the Morris water maze task. Autoradiography results showed that long-term treatment reduced insulin binding in the thalamus but not the hippocampus. Results from hippocampal immunofluorescence revealed age-related decreases in insulin immunoreactivity that were partially offset by intranasal administration. Microarray analyses highlighted numerous insulin-sensitive genes, suggesting insulin aspart was able to enter the brain and alter hippocampal RNA expression patterns including those associated with tumor suppression. Our work provides insights into potential mechanisms of intranasal insulin and insulin resistance, and highlights the importance of treatment duration and the brain regions targeted.
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Affiliation(s)
| | | | - Emily Sudkamp
- The College of Pharmacy, University of Kentucky, Lexington, Kentucky
| | | | | | - Grant Fox
- Department of Pharmacology and Nutritional Sciences
| | | | - Mengfan Xia
- Department of Pharmacology and Nutritional Sciences
| | | | | | | | - James R Pauly
- The College of Pharmacy, University of Kentucky, Lexington, Kentucky
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11
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Frazier HN, Anderson KL, Ghoweri AO, Lin RL, Hawkinson TR, Popa GJ, Sompol P, Mendenhall MD, Norris CM, Thibault O. Molecular elevation of insulin receptor signaling improves memory recall in aged Fischer 344 rats. Aging Cell 2020; 19:e13220. [PMID: 32852134 PMCID: PMC7576226 DOI: 10.1111/acel.13220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/16/2020] [Accepted: 07/22/2020] [Indexed: 12/24/2022] Open
Abstract
As demonstrated by increased hippocampal insulin receptor density following learning in animal models and decreased insulin signaling, receptor density, and memory decline in aging and Alzheimer's diseases, numerous studies have emphasized the importance of insulin in learning and memory processes. This has been further supported by work showing that intranasal delivery of insulin can enhance insulin receptor signaling, alter cerebral blood flow, and improve memory recall. Additionally, inhibition of insulin receptor function or expression using molecular techniques has been associated with reduced learning. Here, we sought a different approach to increase insulin receptor activity without the need for administering the ligand. A constitutively active, modified human insulin receptor (IRβ) was delivered to the hippocampus of young (2 months) and aged (18 months) male Fischer 344 rats in vivo. The impact of increasing hippocampal insulin receptor expression was investigated using several outcome measures, including Morris water maze and ambulatory gait performance, immunofluorescence, immunohistochemistry, and Western immunoblotting. In aged animals, the IRβ construct was associated with enhanced performance on the Morris water maze task, suggesting that this receptor was able to improve memory recall. Additionally, in both age-groups, a reduced stride length was noted in IRβ-treated animals along with elevated hippocampal insulin receptor levels. These results provide new insights into the potential impact of increasing neuronal insulin signaling in the hippocampus of aged animals and support the efficacy of molecularly elevating insulin receptor activity in vivo in the absence of the ligand to directly study this process.
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Affiliation(s)
| | - Katie L. Anderson
- Department of Pharmacology and Nutritional SciencesLexingtonKentuckyUSA
| | - Adam O. Ghoweri
- Department of Pharmacology and Nutritional SciencesLexingtonKentuckyUSA
| | - Ruei-Lung Lin
- Department of Pharmacology and Nutritional SciencesLexingtonKentuckyUSA
| | - Tara R. Hawkinson
- Department of Pharmacology and Nutritional SciencesLexingtonKentuckyUSA
| | - Gabriel J. Popa
- Department of Molecular and Cellular BiochemistryLexingtonKentuckyUSA
| | - Pradoldej Sompol
- Sanders-Brown Center on AgingUniversity of KentuckyLexingtonKentuckyUSA
| | | | | | - Olivier Thibault
- Department of Pharmacology and Nutritional SciencesLexingtonKentuckyUSA
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12
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Rhea EM, Raber J, Banks WA. ApoE and cerebral insulin: Trafficking, receptors, and resistance. Neurobiol Dis 2020; 137:104755. [PMID: 31978603 PMCID: PMC7050417 DOI: 10.1016/j.nbd.2020.104755] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/13/2020] [Accepted: 01/20/2020] [Indexed: 12/16/2022] Open
Abstract
Central nervous system (CNS) insulin resistance is associated with Alzheimer's disease (AD). In addition, the apolipoprotein E4 (apoE4) isoform is a risk factor for AD. The connection between these two factors in relation to AD is being actively explored. We summarize this literature with a focus on the transport of insulin and apoE across the blood-brain barrier (BBB) and into the CNS, the impact of apoE and insulin on the BBB, and the interactions between apoE, insulin, and the insulin receptor once present in the CNS. We highlight how CNS insulin resistance is apparent in AD and potential ways to overcome this resistance by repurposing currently approved drugs, with apoE genotype taken into consideration as the treatment response following most interventions is apoE isoform-dependent. This review is part of a special issue focusing on apoE in AD and neurodegeneration.
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Affiliation(s)
- Elizabeth M Rhea
- Research and Development, Veterans Affairs Puget Sound Healthcare System, Seattle, WA 98108, United States of America; Department of Medicine, University of Washington, Seattle, WA 98195, United States of America.
| | - Jacob Raber
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, United States of America; Departments of Neurology and Radiation Medicine, Division of Neuroscience, ONPRC, Oregon Health & Science University, Portland, OR 97239, United States of America
| | - William A Banks
- Research and Development, Veterans Affairs Puget Sound Healthcare System, Seattle, WA 98108, United States of America; Department of Medicine, University of Washington, Seattle, WA 98195, United States of America
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13
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Sanguinetti E, Guzzardi MA, Panetta D, Tripodi M, De Sena V, Quaglierini M, Burchielli S, Salvadori PA, Iozzo P. Combined Effect of Fatty Diet and Cognitive Decline on Brain Metabolism, Food Intake, Body Weight, and Counteraction by Intranasal Insulin Therapy in 3×Tg Mice. Front Cell Neurosci 2019; 13:188. [PMID: 31130848 PMCID: PMC6509878 DOI: 10.3389/fncel.2019.00188] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 04/12/2019] [Indexed: 11/13/2022] Open
Abstract
Obesity and cognitive decline can occur in association. Brain dysmetabolism and insulin resistance might be common underlying traits. We aimed to examine the effect of high-fat diet (HFD) on cognitive decline, and of cognitive impairment on food intake and body-weight, and explore efficacy of chronic intranasal insulin (INI) therapy. We used control (C) and triple transgenic mice (3×Tg, a model of Alzheimer's pathology) to measure cerebral mass, glucose metabolism, and the metabolic response to acute INI administration (cerebral insulin sensitivity). Y-Maze, positron emission-computed tomography, and histology were employed in 8 and 14-month-old mice, receiving normal diet (ND) or HFD. Chronic INI therapy was tested in an additional 3×Tg-HFD group. The 3×Tg groups overate, and had lower body-weight, but similar BMI, than diet-matched controls. Cognitive decline was progressive from HFD to 3×Tg-ND to 3×Tg-HFD. At 8 months, brain fasting glucose uptake (GU) was increased by C-HFD, and this effect was blunted in 3×Tg-HFD mice, also showing brain insulin resistance. Brain mass was reduced in 3×Tg mice at 14 months. Dentate gyrus dimensions paralleled cognitive findings. Chronic INI preserved cognition, dentate gyrus and metabolism, reducing food intake, and body weight in 3×Tg-HFD mice. Peripherally, leptin was suppressed and PAI-1 elevated in 3×Tg mice, correlating inversely with cerebral GU. In conclusion, 3×Tg background and HFD exert additive (genes*lifestyle) detriment to the brain, and cognitive dysfunction is accompanied by increased food intake in 3×Tg mice. PAI-1 levels and leptin deficiency were identified as potential peripheral contributors. Chronic INI improved peripheral and central outcomes.
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Affiliation(s)
- Elena Sanguinetti
- Institute of Clinical Physiology, National Research Council (CNR), Pisa, Italy.,Scuola Superiore di Studi Universitari Sant'Anna, Pisa, Italy
| | | | - Daniele Panetta
- Institute of Clinical Physiology, National Research Council (CNR), Pisa, Italy
| | - Maria Tripodi
- Institute of Clinical Physiology, National Research Council (CNR), Pisa, Italy
| | - Vincenzo De Sena
- Institute of Clinical Physiology, National Research Council (CNR), Pisa, Italy
| | - Mauro Quaglierini
- Institute of Clinical Physiology, National Research Council (CNR), Pisa, Italy
| | | | - Piero A Salvadori
- Institute of Clinical Physiology, National Research Council (CNR), Pisa, Italy
| | - Patricia Iozzo
- Institute of Clinical Physiology, National Research Council (CNR), Pisa, Italy
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14
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Frazier HN, Ghoweri AO, Anderson KL, Lin RL, Porter NM, Thibault O. Broadening the definition of brain insulin resistance in aging and Alzheimer's disease. Exp Neurol 2019; 313:79-87. [PMID: 30576640 PMCID: PMC6370304 DOI: 10.1016/j.expneurol.2018.12.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/05/2018] [Accepted: 12/17/2018] [Indexed: 12/17/2022]
Abstract
It has been >20 years since studies first revealed that the brain is insulin sensitive, highlighted by the expression of insulin receptors in neurons and glia, the presence of circulating brain insulin, and even localized insulin production. Following these discoveries, evidence of decreased brain insulin receptor number and function was reported in both clinical samples and animal models of aging and Alzheimer's disease, setting the stage for the hypothesis that neuronal insulin resistance may underlie memory loss in these conditions. The development of therapeutic insulin delivery to the brain using intranasal insulin administration has been shown to improve aspects of memory or learning in both humans and animal models. However, whether this approach functions by compensating for poorly signaling insulin receptors, for reduced insulin levels in the brain, or for reduced trafficking of insulin into the brain remains unclear. Direct measures of insulin's impact on cellular physiology and metabolism in the brain have been sparse in models of Alzheimer's disease, and even fewer studies have analyzed these processes in the aged brain. Nevertheless, recent evidence supports the role of brain insulin as a mediator of glucose metabolism through several means, including altering glucose transporters. Here, we provide a review of contemporary literature on brain insulin resistance, highlight the rationale for improving memory function using intranasal insulin, and describe initial results from experiments using a molecular approach to more directly measure the impact of insulin receptor activation and signaling on glucose uptake in neurons.
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Affiliation(s)
- Hilaree N Frazier
- University of Kentucky, Department of Pharmacology and Nutritional Sciences, 800 Rose St., Lexington, KY 40536, United States.
| | - Adam O Ghoweri
- University of Kentucky, Department of Pharmacology and Nutritional Sciences, 800 Rose St., Lexington, KY 40536, United States.
| | - Katie L Anderson
- University of Kentucky, Department of Pharmacology and Nutritional Sciences, 800 Rose St., Lexington, KY 40536, United States.
| | - Ruei-Lung Lin
- University of Kentucky, Department of Pharmacology and Nutritional Sciences, 800 Rose St., Lexington, KY 40536, United States.
| | - Nada M Porter
- University of Kentucky, Department of Pharmacology and Nutritional Sciences, 800 Rose St., Lexington, KY 40536, United States.
| | - Olivier Thibault
- University of Kentucky, Department of Pharmacology and Nutritional Sciences, 800 Rose St., Lexington, KY 40536, United States.
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15
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Gabbouj S, Natunen T, Koivisto H, Jokivarsi K, Takalo M, Marttinen M, Wittrahm R, Kemppainen S, Naderi R, Posado-Fernández A, Ryhänen S, Mäkinen P, Paldanius KM, Doria G, Poutiainen P, Flores O, Haapasalo A, Tanila H, Hiltunen M. Intranasal insulin activates Akt2 signaling pathway in the hippocampus of wild-type but not in APP/PS1 Alzheimer model mice. Neurobiol Aging 2019; 75:98-108. [DOI: 10.1016/j.neurobiolaging.2018.11.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 11/02/2018] [Accepted: 11/12/2018] [Indexed: 12/15/2022]
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16
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Hernandez AR, Hernandez CM, Campos K, Truckenbrod L, Federico Q, Moon B, McQuail JA, Maurer AP, Bizon JL, Burke SN. A Ketogenic Diet Improves Cognition and Has Biochemical Effects in Prefrontal Cortex That Are Dissociable From Hippocampus. Front Aging Neurosci 2018; 10:391. [PMID: 30559660 PMCID: PMC6286979 DOI: 10.3389/fnagi.2018.00391] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 11/08/2018] [Indexed: 12/22/2022] Open
Abstract
Age-related cognitive decline has been linked to a diverse set of neurobiological mechanisms, including bidirectional changes in proteins critical for neuron function. Importantly, these alterations are not uniform across the brain. For example, the hippocampus (HPC) and prefrontal cortex (PFC) show distinct patterns of dysfunction in advanced age. Because higher cognitive functions require large–scale interactions across prefrontal cortical and hippocampal networks, selectively targeting an alteration within one region may not broadly restore function to improve cognition. One mechanism for decline that the PFC and HPC share, however, is a reduced ability to utilize glucose for energy metabolism. Although this suggests that therapeutic strategies bypassing the need for neuronal glycolysis may be beneficial for treating cognitive aging, this approach has not been empirically tested. Thus, the current study used a ketogenic diet (KD) as a global metabolic strategy for improving brain function in young and aged rats. After 12 weeks, rats were trained to perform a spatial alternation task through an asymmetrical maze, in which one arm was closed and the other was open. Both young and aged KD-fed rats showed resilience against the anxiogenic open arm, training to alternation criterion performance faster than control animals. Following alternation testing, rats were trained to perform a cognitive dual task that required working memory while simultaneously performing a bi-conditional association task (WM/BAT), which requires PFC–HPC interactions. All KD-fed rats also demonstrated improved performance on WM/BAT. At the completion of behavioral testing, tissue punches were collected from the PFC for biochemical analysis. KD-fed rats had biochemical alterations within PFC that were dissociable from previous results in the HPC. Specifically, MCT1 and MCT4, which transport ketone bodies, were significantly increased in KD-fed rats compared to controls. GLUT1, which transports glucose across the blood brain barrier, was decreased in KD-fed rats. Contrary to previous observations within the HPC, the vesicular glutamate transporter (VGLUT1) did not change with age or diet within the PFC. The vesicular GABA transporter (VGAT), however, was increased within PFC similar to HPC. These data suggest that KDs could be optimal for enhancing large-scale network function that is critical for higher cognition.
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Affiliation(s)
- Abbi R Hernandez
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Caesar M Hernandez
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Keila Campos
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Leah Truckenbrod
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Quinten Federico
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Brianna Moon
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Joseph A McQuail
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Andrew P Maurer
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Jennifer L Bizon
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
| | - Sara N Burke
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States.,Institute on Aging, University of Florida, Gainesville, FL, United States
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17
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Chapman CD, Schiöth HB, Grillo CA, Benedict C. Intranasal insulin in Alzheimer's disease: Food for thought. Neuropharmacology 2018; 136:196-201. [PMID: 29180222 PMCID: PMC10523803 DOI: 10.1016/j.neuropharm.2017.11.037] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 11/20/2017] [Accepted: 11/22/2017] [Indexed: 12/26/2022]
Abstract
Accumulating evidence suggests that disrupted brain insulin signaling promotes the development and progression of Alzheimer's disease (AD), driving clinicians to target this circuitry. While both traditional and more modern antidiabetics show promise in combating insulin resistance, intranasal insulin appears to be the most efficient method of boosting brain insulin. Furthermore, intranasal delivery elegantly avoids adverse effects from peripheral insulin administration. However, there remain significant open questions regarding intranasal insulin's efficacy, safety, and potential as an adjunct or mono-therapy. Thus, this review aims to critically evaluate the present evidence and future potential of intranasal insulin as a meaningful treatment for AD. This article is part of the Special Issue entitled 'Metabolic Impairment as Risk Factors for Neurodegenerative Disorders.'
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Affiliation(s)
- Colin D Chapman
- Department of Neuroscience, Uppsala University, SE-751 24 Uppsala, Sweden.
| | - Helgi B Schiöth
- Department of Neuroscience, Uppsala University, SE-751 24 Uppsala, Sweden
| | - Claudia A Grillo
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina - School of Medicine, Columbia, SC 29209, USA
| | - Christian Benedict
- Department of Neuroscience, Uppsala University, SE-751 24 Uppsala, Sweden
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18
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Duarte A, Santos M, Oliveira C, Moreira P. Brain insulin signalling, glucose metabolism and females' reproductive aging: A dangerous triad in Alzheimer's disease. Neuropharmacology 2018; 136:223-242. [DOI: 10.1016/j.neuropharm.2018.01.044] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 01/22/2018] [Accepted: 01/29/2018] [Indexed: 12/12/2022]
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19
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Frazier HN, Anderson KL, Maimaiti S, Ghoweri AO, Kraner SD, Popa GJ, Hampton KK, Mendenhall MD, Norris CM, Craven RJ, Thibault O. Expression of a Constitutively Active Human Insulin Receptor in Hippocampal Neurons Does Not Alter VGCC Currents. Neurochem Res 2018; 44:269-280. [PMID: 29572644 DOI: 10.1007/s11064-018-2510-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/16/2018] [Accepted: 03/19/2018] [Indexed: 01/30/2023]
Abstract
Memory and cognitive decline are the product of numerous physiological changes within the aging brain. Multiple theories have focused on the oxidative, calcium, cholinergic, vascular, and inflammation hypotheses of brain aging, with recent evidence suggesting that reductions in insulin signaling may also contribute. Specifically, a reduction in insulin receptor density and mRNA levels has been implicated, however, overcoming these changes remains a challenge. While increasing insulin receptor occupation has been successful in offsetting cognitive decline, alternative molecular approaches should be considered as they could bypass the need for brain insulin delivery. Moreover, this approach may be favorable to test the impact of continued insulin receptor signaling on neuronal function. Here we used hippocampal cultures infected with lentivirus with or without IRβ, a constitutively active, truncated form of the human insulin receptor, to characterize the impact continued insulin receptor signaling on voltage-gated calcium channels. Infected cultures were harvested between DIV 13 and 17 (48 h after infection) for Western blot analysis on pAKT and AKT. These results were complemented with whole-cell patch-clamp recordings of individual pyramidal neurons starting 96 h post-infection. Results indicate that while a significant increase in neuronal pAKT/AKT ratio was seen at the time point tested, effects on voltage-gated calcium channels were not detected. These results suggest that there is a significant difference between constitutively active insulin receptors and the actions of insulin on an intact receptor, highlighting potential alternate mechanisms of neuronal insulin resistance and mode of activation.
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Affiliation(s)
- H N Frazier
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, 800 Rose Street, Lexington, KY, 40536, USA
| | - K L Anderson
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, 800 Rose Street, Lexington, KY, 40536, USA
| | - S Maimaiti
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, 800 Rose Street, Lexington, KY, 40536, USA
| | - A O Ghoweri
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, 800 Rose Street, Lexington, KY, 40536, USA
| | - S D Kraner
- Sanders Brown Center on Aging, University of Kentucky Medical Center, UKMC, 800 S. Limestone, Lexington, KY, 40536, USA
| | - G J Popa
- Department of Molecular and Cellular Biochemistry, University of Kentucky Medical Center, UKMC, 741 S. Limestone, Lexington, KY, 40536, USA
| | - K K Hampton
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, 800 Rose Street, Lexington, KY, 40536, USA
| | - M D Mendenhall
- Department of Molecular and Cellular Biochemistry, University of Kentucky Medical Center, UKMC, 741 S. Limestone, Lexington, KY, 40536, USA
| | - C M Norris
- Sanders Brown Center on Aging, University of Kentucky Medical Center, UKMC, 800 S. Limestone, Lexington, KY, 40536, USA
| | - R J Craven
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, 800 Rose Street, Lexington, KY, 40536, USA
| | - O Thibault
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, 800 Rose Street, Lexington, KY, 40536, USA.
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20
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Tytell M, Davis AT, Giles J, Snider LC, Xiao R, Dozier SG, Presley TD, Kavanagh K. Alfalfa-derived HSP70 administered intranasally improves insulin sensitivity in mice. Cell Stress Chaperones 2018; 23:189-194. [PMID: 28822083 PMCID: PMC5823803 DOI: 10.1007/s12192-017-0835-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 12/15/2022] Open
Abstract
Heat shock protein (HSP) 70 is an abundant cytosolic chaperone protein that is deficient in insulin-sensitive tissues in diabetes and unhealthy aging, and is considered a longevity target. It is also protective in neurological disease models. Using HSP70 purified from alfalfa and administered as an intranasal solution, we tested in whether the administration of Hsp70 to diet-induced diabetic mice would improve insulin sensitivity. Both the 10 and 40 μg given three times per week for 26 days significantly improved the response to insulin. The HSP70 was found to pass into the olfactory bulbs within 4-6 hours of a single dose. These results suggest that a relatively inexpensive, plentiful source of HSP70 administered in a simple, non-invasive manner, has therapeutic potential in diabetes.
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Affiliation(s)
- Michael Tytell
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC, 27157, USA.
| | - Ashley T Davis
- Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC, 27157, USA
| | - Jareca Giles
- Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC, 27157, USA
| | - Lauren C Snider
- Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC, 27157, USA
| | - Ruoyu Xiao
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC, 27157, USA
| | - Stephen G Dozier
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC, 27157, USA
| | - Tennille D Presley
- Department of Chemistry, Winston-Salem State University, 601 S. Martin Luther King, Jr Drive, Winston-Salem, NC, 27110, USA
| | - Kylie Kavanagh
- Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC, 27157, USA
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21
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Maimaiti S, Frazier HN, Anderson KL, Ghoweri AO, Brewer LD, Porter NM, Thibault O. Novel calcium-related targets of insulin in hippocampal neurons. Neuroscience 2017; 364:130-142. [PMID: 28939258 DOI: 10.1016/j.neuroscience.2017.09.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 09/07/2017] [Accepted: 09/08/2017] [Indexed: 01/28/2023]
Abstract
Both insulin signaling disruption and Ca2+ dysregulation are closely related to memory loss during aging and increase the vulnerability to Alzheimer's disease (AD). In hippocampal neurons, aging-related changes in calcium regulatory pathways have been shown to lead to higher intracellular calcium levels and an increase in the Ca2+-dependent afterhyperpolarization (AHP), which is associated with cognitive decline. Recent studies suggest that insulin reduces the Ca2+-dependent AHP. Given the sensitivity of neurons to insulin and evidence that brain insulin signaling is reduced with age, insulin-mediated alterations in calcium homeostasis may underlie the beneficial actions of insulin in the brain. Indeed, increasing insulin signaling in the brain via intranasal delivery has yielded promising results such as improving memory in both clinical and animal studies. However, while several mechanisms have been proposed, few have focused on regulation on intracellular Ca2+. In the present study, we further examined the effects of acute insulin on calcium pathways in primary hippocampal neurons in culture. Using the whole-cell patch-clamp technique, we found that acute insulin delivery reduced voltage-gated calcium currents. Fura-2 imaging was used to also address acute insulin effects on spontaneous and depolarization-mediated Ca2+ transients. Results indicate that insulin reduced Ca2+ transients, which appears to have involved a reduction in ryanodine receptor function. Together, these results suggest insulin regulates pathways that control intracellular Ca2+ which may reduce the AHP and improve memory. This may be one mechanism contributing to improved memory recall in response to intranasal insulin therapy in the clinic.
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Affiliation(s)
- Shaniya Maimaiti
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Hilaree N Frazier
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Katie L Anderson
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Adam O Ghoweri
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Lawrence D Brewer
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Nada M Porter
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Olivier Thibault
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States.
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22
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Rhea EM, Humann SR, Nirkhe S, Farr SA, Morley JE, Banks WA. Intranasal Insulin Transport is Preserved in Aged SAMP8 Mice and is Altered by Albumin and Insulin Receptor Inhibition. J Alzheimers Dis 2017; 57:241-252. [PMID: 28222522 DOI: 10.3233/jad-161095] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Insulin delivered to the level of the cribriform plate (intranasal insulin) is being investigated for its ability to enhance memory in people with Alzheimer's disease (AD). Recent work has shown intranasal insulin can be detected in young CD-1 mice within 5 min and is still present 60 min after injection. The current study determined whether intranasal insulin transport and the subsequent brain distribution of insulin varies in young, healthy mice (CD-1) compared to those with an AD-like phenotype (aged SAMP8) or those pre-disposed to develop such a phenotype (young SAMP8). We showed transport does not vary among these three mouse cohorts, suggesting that intranasal uptake and brain pharmacokinetics do not differ with AD-like signs or the genetic predisposition to developing them. We found that co-administration with bovine serum albumin increased levels of insulin in most brain regions. In addition, the insulin receptor inhibitor, S961, decreases the amount of insulin transported throughout the brain after intranasal injection. These results show insulin delivery to the brain by intranasal administration can be modified with agents such as albumin, may be dependent on the insulin receptor, and is not affected by an AD-like phenotype as presented by the SAMP8 mouse.
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Affiliation(s)
- Elizabeth M Rhea
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | | | - Surabhi Nirkhe
- University of Washington School of Medicine, Seattle, WA, USA
| | - Susan A Farr
- Department of Internal Medicine, Division of Geriatrics, Saint Louis University, St. Louis, MO, USA
- Research and Development Service, VA Medical Center, St. Louis, MO, USA
| | - John E Morley
- Department of Internal Medicine, Division of Geriatrics, Saint Louis University, St. Louis, MO, USA
| | - William A Banks
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington School of Medicine, Seattle, WA, USA
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